1. Field of the Invention
This invention is related to an Always on Dynamic Integrated Services Digital Network (AO/DI) service and, more particularly, for automatically changing the Always-On-Dynamic Integrated Services Digital Network""s (AO/DI""s) thresholds that increase or decrease in bandwidth for effecting a corresponding change in the rate of data transfer capacity for an AO/DI subscriber.
2. Description of the Problem Solved
With the increased use of the Internet, World Wide Web, and other networks, the need for increasing access bandwidth to these networks has grown. The Integrated Services Digital Network (ISDN) protocol architecture using a Basic Rate Interface (BRI) user interface is widely used for network access and is relatively high speed. BRI consists of one D-channel and two B-channels. The D-channel has a bandwidth of 16 kilo-bytes-per-second (kbps). The D-channel transfers data through a packet switched network to the Internet (or other Networks). The D-channel is always active and, therefore, is primarily used for transfer of data that does not require high bandwidth and to exchange control information between the user and the network for call establishment and termination. The two B-channels are bearer communication channels. Each B-channel can carry voice, video or packet data at a bandwidth rate of 64 kbps. To transfer data at a rate faster than 64 kbps through a network from one end-point to another destination, the two B-channels in a BRI can be aggregated to provide a total bit rate of 128 kbps. The technique of aggregating two B-channels is called an aggregation of multiple links, and is known as inverse multiplexing. Inverse multiplexing is more thoroughly described in the article entitled xe2x80x9cThe PPP Multilink Protocol,xe2x80x9d RFC 2125, March 1997, and which is incorporated herein by reference. The B-channels are carried through a circuit switched network and are not always on, but are seized and released depending on the need for access capacity. The D-channel is used to carry the requests for seizing and releasing B-channels.
For example, the D-channel can be used to transmit messages that setup a telephone call (a request for a B-channel) through a network from a calling party to a called party. The D-channel can also transmit packet data through the network to notify a calling party that the called party""s telephone is ringing and whether the called party has answered the telephone call.
Although data can be transferred faster through a network by aggregating two B-channels of a BRI to serve one end user, it is recognized that it does have a cost. For example, aggregating two B-channels requires the use of two Digital Signal Level 0 (DS0) circuits in the circuit switched network, instead of one DS0. This results in higher end user, Local Exchange Carrier (LEC) and Internet Service Provider (ISP) cost. Furthermore, it is recognized that end users do not always need the B-channels, when they are reading an e-mail message or have walked away from the computer.
To control these end user, LEC and ISP high costs and still provide two channel bandwidth when needed, the present invention employs AO/DI networking services for fast transfer of data through a network without these higher costs. AO/DI networking services provide an always available connection via the D-channel of BRI to packet-based networks through the Wide Area Network (WAN). AO/DI networking services reduce the costs for the end user by using the D-channel to make low-speed data transfers. For ISPs, AO/DI networking removes a significant amount of holding time from the circuit switched connections (B-channels). Since the D-channel is always available, the customer premises equipment (CPE) can use the D-channel to pass Multilink Point-to-Point and TCP/IP protocols encapsulated in X.25 protocols.
Optionally, when D-channel bandwidth exceeds a defined threshold, the end user computer places one or more ISDN B-channel calls to increase bandwidth. When bandwidth requirements fall below a defined threshold, the B-channel or B-channels are released. AO/DI networking services use the D-channel of BRI to maintain a constant virtual connection to a central office switch in the circuit switched network. In this mode, the 16 kbps D-channel is capable of receiving and transmitting data, in addition to control signals, at 9.6 kbps. This bandwidth is quite suitable for transforming e-mail, stock quotes or news updates. When higher speed data transfers are required, such as downloading Web pages, one or both of the B-channels in the BRI can be activated automatically to transfer the data at bandwidths of 64 kbps or 128 kbps, respectively.
The AO/DI networking configuration uses a Bandwidth Allocation Protocol (BAP) and its associated control protocol, the Bandwidth Allocation Control Protocol (BACP), to transfer data and commands via the network between an end user and the end user""s serving ISP. BAP provides a means (via datagrams) to implement dynamically adding and/or removing individual links (B-channels) from a multilink bundle, such as BRI.
BAP and BACP provide a flexible yet robust way of managing bandwidth between two end users. BAP does this by defining Call-Control packets and a protocol that allows end users to coordinate the actual bandwidth allocation and de-allocation. BAP can be used to manage the number of links in a multilink bundle. BAP and BACP are well known in the art. More information about BAP and BACP may be found in the publication entitled xe2x80x9cThe PPP Multilink 10 Protocol,xe2x80x9d RFC 2125, March 1997, and which has been incorporated herein above by reference.
In operation, an end user implementing AO/DI networking services will generally need an AO/DI card. This AO/DI card is integrated with the endxe2x80x2 user""s computer and serves as the computer""s interface to an ISP via a circuit switched network and a packet switched network. The AO/DI card and ISP communicates with each other using BAPIBACP. The AO/DI card has default threshold parameters set to trigger a message to the ISP, asking for agreement from the ISP to request the circuit switched network to establish certain B-channel connections from the end user""s computer to the ISP. Likewise, the ISP has threshold parameters set to trigger a message to the end user, instructing the end user to request the circuit switched network to establish certain B-channel connections between the end user""s computer and the ISP. These messages are sent via an already established D-channel connection between the end user""s computer and the ISP. For example, if the end user is transmitting information to the ISP, based on default threshold parameters of the AO/DI card, the end user may make a requestxe2x80x94via the D-channelxe2x80x94to add a B-channel. The end user makes this request to the ISP via the D-channel connection using BAP/BACP to ask if the ISP is willing to add or remove B-channels from the end user to ISP. If the ISP agrees, the end user will initiate a call (acquisition of a B-channel) or release. The AO/DI card has a threshold table that is comprised of a set of threshold parameters that are used to trigger, when a message is to be sent from the end user""s computer to an ISP. This message requests agreement with the ISP for request to the LEC to add or remove B-channels from the end user to the ISP via the circuit switched network. The threshold parameters of the AO/DI card are generally set to certain default parameters before the card is integrated with a computer. These threshold parameters cannot be readily changed. For example, an AO/DI card might be set to trigger sending a message to add one B-channel of a BRI if the end user is sending data at a bandwidth of greater than 7.5 kbps through a network and to remove the B-channel when the bandwidth decreases to less than 5.0 kbps; thereby, reverting back to sending data via the D-channel. The AO/DI card might be set to trigger sending a message to add both B-channels if the end user is sending data through the network at a bandwidth of greater than 48 kbps and to remove one of the B-channels if the bandwidth decreases to less than 32 kbps.
The ISP can also advise end users on when to add or remove a B-channel.
For example, if a large file is being sent to the end user, the ISP can issue BAP messages to the end user, requesting the end user to initiate a request for a B-channel.
A common problem that might be encountered with the above mentioned method of managing bandwidth is that the end user and the ISP might not make xe2x80x9cgoodxe2x80x9d choices in requesting more or less B-channels pursuant to their threshold parameter settings. For example, AO/DI network users might want to minimize B-channel usage but still transfer data quickly through a network. Therefore, these end users would have their threshold parameters set to aggressively request extra B-channels, and to drop the B-channels if they are not heavily used for even a second. This would save telephone circuits in the circuit switched network (even when there are many available) and exhaust the circuit switched network""s real-time capacity because of the large number of call attempts. The LEC sets up one B-channel at a time. If the LEC receives too many requests to set up B-channels at once, the LEC will be backlogged until it can process each request. Therefore, if end users request the LEC to setup a circuit when the LEC is having RT problems, the request will only add to the backlog in the circuit switched network, thereby causing further delays in setting up a telephone circuit and frustrating the end user. Likewise, if all the telephone circuits in the circuit switched network are in use when an end user requests a B-channel, the LEC cannot make such connection until a B-channel becomes available.
Thus, an object of this invention is to provide a way in which to notify an ISP, connected to a circuit switched network, the status of telephone circuits and real-time availability in the circuit switched network serving the ISP and the ISP""s customers.
Another object of this invention is to provide a way in which to determine new threshold parameters for an AO/DI card of an end user""s computer, based on the status of telephone circuits and real-time availability in the circuit switched network serving the computer containing the AO/DI card.
A further object of this invention is to provide a way in which to replace the threshold parameters of an ISP based on the status of telephone and real-time availability circuits in a circuit switched network serving the ISP.
A still fuirther object of this invention is to provide a way in which to replace the threshold parameters of an AO/DI card based on the status of telephone circuits and real-time availability in a circuit switched network serving the computer containing the AO/DI card.
It is another object of the invention to provide a way in which two new datagram types can be added to the BAP protocol which allows the exchange of parameters that drive the requests to connect and/or disconnect B-channels between an end user and an ISP via a circuit switched network.
It is a further object of this invention to provide a protocol that would contain parameters which could be used by two ends of a multilink bundle, such as a BRI, to influence the link requests.
The present invention solves the above problems by providing an enhanced AO/DIxe2x80x94called System Optimized AO/DI (SOAO/DI). SOAO/DI automatically updates threshold parameters of an AO/DI card integrated within a computer, based on the status of telephone circuits and real-time availability in a circuit switched network serving both the computer and the computer""s serving ISP. The SOAO/DI network comprises a circuit switched network having an end office with a network management center. The network management center monitors the circuit switched network. A packet switched network is connected to the end office. The packet switched network has a packet handler. The AO/DI card is connected to both the computer and the packet handler via the end office. An ISP is connected to both the packet handler and the end office. The ISP determines the status of telephone circuits or real-time availability in the circuit switched network serving both the computer and the ISP. Alternatively, the network management center could provide information to the ISP, regarding the status of telephone circuits and real-time availability in the circuit switched network and send proper new threshold parameters for the AO/DI card and ISP threshold tables.
The method of the present invention provides a way to automatically update threshold parameters of the ISP and default threshold parameters of the AO/DI card. The threshold parameters of the AO/DI card defmes when the AO/DI card requests an ISP computer to open or close at least one B-channel in the circuit switched network between the computer and the ISP. The ISP or network management center determines the status of telephone circuits and real-time availability of the circuit switched network serving both the ISP and the computer. Accordingly, either the ISP or network management center can determine the new threshold parameters for replacing threshold parameters of both the AO/DI card and the ISP. Once the new threshold parameters have been determined, the ISP automatically replaces its threshold parameters with the new threshold parameters. The ISP then builds a message containing the new threshold parameters and sends the message to the computer, whereby the computer automatically replaces the threshold parameters of its AO/DI card with the new threshold parameters.